Kourtney Kardashian has reportedly taken major issue with model Sofia Richie, the teenage girlfriend of her former partner Scott Disick.

Months into the couple's romance, an insider claims the 38-year-old Keeping Up With The Kardashians star has grown tired of seeing Richie with her three kids and wants her to "back the f**k off" when it comes to spending time with 8-year-old Mason, 5-year-old Penelope, and 3-year-old Reign.

“Kourtney flipped out and she told Scott that Sofia needs to back the f**k off right now before she makes her back off,” a source told Radar Online on March 28. 

Sofia Richie Doesn't Care

Unfortunately, the young Richie, 19, reportedly doesn't care how Kardashian feels about her being around the kids and has informed her boyfriend that she isn't going to change her behavior just because Kardashian isn't happy. She's even supposedly told the three kids that they can call her "stepmom Sofia."

According to the report, Richie actually feels Kris Jenner, Kardashian's mom and the children's grandmom, is on her side because she loves the idea of a love triangle.

“She also knows that she is getting paid more to be on the show than Kourtney’s boyfriend, Younes,” the source continued.

Richie has been involved in a romance with Disick since the end of last summer and Kardashian and Younes Bendjima have been dating for just as long -- if not much longer. As fans may recall, the couple began hanging out with one another in Paris in 2016 but didn't confirm they were dating until many months later.

New 'KUWTK' Characters?

While Richie and Bendjima, 24, have not yet been featured on the show, their relationships with Disick, 34, and Kardashian, respectively, have been mentioned on the series and rumors have swirled for months in regard to their possibly upcoming appearances.

The Radar Online source claimed Jenner has been staying close to Disick in recent months and Kardashian reportedly knows that her mother would put ratings for their show ahead of her family's own good.

Kardashian and Disick dated for 9 years before calling it quits in July 2015. Since then, they have both been linked to several different people and their relationship with one another has remained strained throughout the time they've spent apart.